This invention relates generally to the construction of vehicle tires and relates, more particularly, to the means and methods for consolidating a tire carcass and for marrying components of a tire during a tire construction process.
During construction of vehicle tires, a tire carcass is built upon a first stage tire-building drum as the drum is rotated about its longitudinal axis, and a roller having a cylindrical surface is subsequently used to consolidate the tire carcass as the cylindrical surface of the roller is pressed against the outer peripheral surface of the tire carcass. The consolidated carcass is thereafter transferred to a second stage (i.e. a rotatable shaping drum) where it awaits the positioning thereon of a belt and tread package of the vehicle tire.
The belt and tread package is constructed on a separate drum, and upon its completion, is transferred to the second stage drum upon which the carcass has already been positioned. During this transfer, the carcass is held upon the second stage drum while the belt and tread package is positioned onto the outer surface of the carcass. Thereafter, the belt and tread package is married to the carcass to form a green tire layup as a roller having a cylindrical surface is pressed against the outer peripheral surface of the tire layup.
In each of the aforedescribed instances in which a roller is used, the roller is supported adjacent the outer surface of the tire component to be engaged by the cylindrical surface of the roller for rotation about an axis which is substantially parallel to the axis of rotation of the tire component. With the roller supported in such a manner and its cylindrical surface in contact with the surface of the tire component, the rotation of the tire component about its rotation axis effects the rotation of the roller along its longitudinal axis. In other words, the roller is not normally rotated about its axis by any means other than through the frictional engagement between the cylindrical surface of the roller and the peripheral surface of the tire carcass or tire layup. At these stages of the tire-building process (i.e. before the green tire layup is cured), the materials comprising the carcass and the belt and tread package are relatively soft and tacky so that the contact between the roller and the outer surface of the belt and tread drum promotes a consolidation or bonding of the materials in the carcass and green tire layup.
Heretofore, a roller used for consolidating a tire carcass and for marrying the belt and tread package to the carcass during a tire construction process has included a hollow piece of foam material which is positioned along a shaft which, in turn, extends along the outer surface of the corresponding tire component desired to be engaged by the cylindrical surface of the roller. The cylindrical surface of the piece of foam material is relatively stiff, and the length of the piece of foam material has commonly been selected (and cut from a length of stock foam material) to correspond with the overall width of the tire carcass or the width of the belt and tread package positioned upon the carcass
The foam piece of material commonly utilized for the roller has been known to be susceptible to wear, is relatively costly, and the stiffness of its surface is incapable of being changed if, for example, a greater or lesser stiffness of the roller would be preferable when pressed against the outer surface of the corresponding tire component. It would be desirable to provide an alternative apparatus which replaces the foam roller of the prior art and whose construction facilitates a prompt adjustment in the length of the roller to correspond to the width of the tire component to be engaged by the roller surface, possesses a greater resistance to wear than does the piece of foam material of the prior art, and accommodates a prompt change-out of roller components to provide the cylindrical surface of the roller with a greater or lesser degree of stiffness.
Accordingly, it is an object of the present invention to provide a new and improved roller assembly having a roller for use in tire construction and which is particularly well-suited for consolidating a tire carcass or for marrying the belt and tread package and a tire carcass to one another.
Another object of the present invention is to provide such an assembly which does not involve a cut-to-length piece of foam material such as that utilized by the prior art.
Still another object of the present invention is to provide such an assembly whose roller length can be easily altered to permit use of the roller on tire carcasses or green tire layups of differing widths.
Yet another object of the present invention is to provide such an assembly which employs a number of roller-providing components which collectively provide the length of the roller and which can be added to or removed from in order to alter the length of the roller.
A further object of the present invention is to provide such an assembly which accommodates a prompt change-out of the roller components for altering the degree of stiffness along the entirety of the peripheral surface of the roller or for providing selected regions of the roller surface with a stiffness which is different from that of other regions of the roller surface.
A still further object of the present invention is to provide such a roller assembly which is uncomplicated in structure, yet effective in operation.